Boris Johnson has suffered a triple blow as the Tories crashed to two by-election defeats, prompting the Conservative Party Chairman Oliver Dowden to quit.

The Conservatives saw a majority of 24,000, or 40.6%, in the Devon seat of Tiverton and Honiton evaporate – a record reverse for the party – as the Liberal Democrats triumphed.

In Wakefield, the Red Wall constituency in West Yorkshire snatched by the Conservatives in 2019, it was Labour that took victory.

Following the results of the by-elections, Conservative Party Chairman Oliver Dowden resigned and said in a letter to the PM: “We cannot carry on with business as usual.”

Politics Hub: Reaction to Boris Johnson’s humiliating double by-election blow

It was the latest electoral mauling for the PM this year after the Tories lost nearly 500 council seats at the start of last month.

Simon Lightwood, who won the Wakefield by-election for Labour said: “I think people are absolutely tired of the lies and deceit we’ve seen from the prime minister and they’re demanding change and tonight is the demonstration of that.”

Richard Foord who took Tiverton and Horniton for the Lib Dems used his acceptance speech to call for Prime Minister Boris Johnson “to go, and go now”, claiming his victory had “sent a shockwave through British politics”.

Mr Johnson has been under pressure over the partygate scandal as well as the cost of living crisis squeezing British household budgets.

That pressure intensified when a no-confidence vote saw 148 Conservative MPs oppose him.

Labour leader Sir Keir Starmer said: “Wakefield has shown the country has lost confidence in the Tories.

“This result is a clear judgement on a Conservative Party that has run out of energy and ideas.”

Liberal Democrat leader Sir Ed Davey said: “The Liberal Democrats have made political history with this stunning win.

“This should be a wake-up call for all those Conservative MPs propping up Boris Johnson. They cannot afford to ignore this result.

“The public is sick of Boris Johnson’s lies and law-breaking and it’s time for Conservative MPs to finally do the right thing and sack him.”

Analysis:

By-election losses will seep like poison into slowly into the Tory bloodstream

Tories suffer some of the worst by-election defeats since 1945

Mr Johnson, who is attending the Commonwealth Heads of Government conference in Rwanda, said ahead of the by-elections that he would be “watching the results with interest” while adding that “by-elections in mid-term are never necessarily easy for any government”.

He suggested it would be “crazy” for him to quit if he lost the two seats.

The by-elections, both in leave-voting constituencies, took place on the sixth anniversary of the Brexit referendum.

They were each triggered by the resignations of Conservative MPs: in Tiverton and Honiton, Neil Parish quit after he admitted to watching pornography on his mobile phone in the Commons chamber; in Wakefield, Imran Ahmad Khan stepped down after being found guilty of sexually assaulting a 15-year-old boy.

It became apparent soon after polls closed that it would be a bad night for the Tories.

Luke Hall, the party’s deputy chair, told Sky News it had been a “challenging campaign” and pointed to the impact of divisions laid bare by the confidence vote.

“I certainly would accept that disunity in political parties means parties do not win elections,” he said.